1. Field of the Invention
The invention relates generally to the field of catheters and, more particularly to the catheterization of organs such as the renal pelvis or the like.
2. Description of the Prior Art
Present procedures for percutaneous introduction of large bore drainage catheters in order to drain blocked cavities or ducts such as the renal pelvis and the biliary duct are, at best, somewhat hazardous. For instance, one widely practiced method for obtaining long term drainage of an obstructed upper urinary tract is to perform a percutaneous nephrostomy which involves catheterization of the renal pelvis. In order to install the drainage catheter, an initial percutaneous puncture into the renal pelvis may be made with a hollow 18 gauge (1.3 mm) needle. Then, a guide wire is advanced inside the needle until properly positioned whereupon the needle is removed over the guide wire. Appropriately sized fascial dilators are then advanced over the guide wire to enlarge the tract so as to facilitate the subsequent passage of the drainage catheter over the guide wire. A similar technique is used to install a drainage catheter into the biliary duct for transhepatic antigrade biliary drainage.
The initial puncture made in attempting to enter the renal pelvis of the kidney or the biliary tract is seldom a direct hit. For this reason, several punctures are commonly required in order to properly position the needle. The resulting damage to the kidney or biliary duct can be very traumatic for the patient, especially since the kidney or biliary duct is usually already traumatized by disease. Thus, physicians would obviously prefer using a smaller gauge needle in making this initial puncture, so as to minimize the damage and resulting trauma caused by multiple punctures.
Suprapublic catheterization methods and devices which involve percutaneous entry by a puncturing device are disclosed in U.S. Pat. No. 3,752,158 to Kariher; U.S. Pat. No. 3,860,006 to Patel; and U.S. Pat. No. 3,924,633 to Cook et al. U.S. Pat. No. 3,640,281 to Robertson and U.S. Pat. No. 3,920,023 to Dye et al. disclose methods for draining the urinary bladder by inserting the catheter transurethrally into the bladder.
Other catheterization devices which may have some general relevance are disclosed in U.S. Pat. No. 2,118,631 to Wappler; U.S. Pat. No. 2,856,934 to Petillo; U.S. Pat. No. 3,804,097 to Rudie; and U.S. Pat. No. 4,212,304 to Finney. None of the above patents, however, discloses a method or apparatus which minimizes the damage and trauma caused by catheterization of cavities or ducts which because of their small size or difficult to reach location commonly require multiple punctures to properly position the catheter.
Accordingly, it is an object of the present invention to provide an apparatus and method which minimizes the damage and trauma caused by catheterization procedures which are commonly characterized by multiple punctures in attempting to properly position the puncturing device.
It is a further object of the present invention to provide an apparatus and method for catheterization which permits the use of a smaller gauge hollow needle than would otherwise be necessary using present devices or techniques.
It is a yet further object of the present invention to provide a method for catheterization using a smaller gauge hollow needle which method is relatively simple to follow and requires relatively inexpensive additional equipment.
These and other objects and advantages of the present invention will become more apparent in the following figures and detailed description.